This invention relates to the art of fire resistant panels used in vehicles and buildings.
Almost all natural and synthetic polymers are flammable. The flammability of construction materials is a matter of great concern in the construction of vehicles and buildings. This is most apparent in the construction of aircraft, ships and other mass transit vehicles, which are regulated by the federal government, and in military transportation. However, local and voluntary standards are also applied to buildings, automobiles and other places where people may be endangered by fire. Therefore, it is very important to improve the resistance of construction materials to fire so that fires may be prevented or the spread of fires may be slowed to allow people to escape.
Most flame retardants act in one of three manners: (1) a nonflammable flame retardant volatilizes in the presence of fire and inhibits the vapor phase combustion of flammable gases produced by a flammable material; (2) the flame retardant encourages the substrate to undergo solid state carbonization in the presence of heat rather than producing combustible gases; or (3) the flame retardant forms a protective coating that insulates the substrate from the fire. See, e.g., 7 Encyclopedia of Polymer Science and Engineering, Flammability, at 179-195 (J. Wiley & Sons), which is incorporated herein by reference. Thermal barriers typically work by reacting to form an insulative coating in the presence of heat. For instance, the coating may soften and foam in the presence of heat, then carbonize to form a rigid carbonaceous insulating foam. In places where there is extreme danger of fire, such as military vessels and aircraft, it is also known to put in layers of highly flame-resistant materials, such as composites of glass or carbon fibers with matrices of BMI, phenolic resins, polyamide, resins, and PEEK.
Several improvements are desirable in existing fireblocking materials. For highly fire-resistant fireblocking structures, it would be desirable to provide greater flame resistance for improved fire protection. For more typical materials of construction it would also be desirable to provide a fireblocking layer that can protect the material from contact with ordinary small flame sources such as cigarettes, improved the resistance of the material to fire, and protect persons near burning structures from molten and dripping polymers.